// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/vlog.h"

#include <stddef.h>

#include <ostream>
#include <utility>

#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"

namespace logging {

const int VlogInfo::kDefaultVlogLevel = 0;

struct VlogInfo::VmodulePattern {
    enum MatchTarget { MATCH_MODULE,
        MATCH_FILE };

    explicit VmodulePattern(const std::string& pattern);

    VmodulePattern();

    std::string pattern;
    int vlog_level;
    MatchTarget match_target;
};

VlogInfo::VmodulePattern::VmodulePattern(const std::string& pattern)
    : pattern(pattern)
    , vlog_level(VlogInfo::kDefaultVlogLevel)
    , match_target(MATCH_MODULE)
{
    // If the pattern contains a {forward,back} slash, we assume that
    // it's meant to be tested against the entire __FILE__ string.
    std::string::size_type first_slash = pattern.find_first_of("\\/");
    if (first_slash != std::string::npos)
        match_target = MATCH_FILE;
}

VlogInfo::VmodulePattern::VmodulePattern()
    : vlog_level(VlogInfo::kDefaultVlogLevel)
    , match_target(MATCH_MODULE)
{
}

VlogInfo::VlogInfo(const std::string& v_switch,
    const std::string& vmodule_switch,
    int* min_log_level)
    : min_log_level_(min_log_level)
{
    DCHECK(min_log_level != NULL);

    int vlog_level = 0;
    if (!v_switch.empty()) {
        if (base::StringToInt(v_switch, &vlog_level)) {
            SetMaxVlogLevel(vlog_level);
        } else {
            DLOG(WARNING) << "Could not parse v switch \"" << v_switch << "\"";
        }
    }

    base::StringPairs kv_pairs;
    if (!base::SplitStringIntoKeyValuePairs(
            vmodule_switch, '=', ',', &kv_pairs)) {
        DLOG(WARNING) << "Could not fully parse vmodule switch \""
                      << vmodule_switch << "\"";
    }
    for (base::StringPairs::const_iterator it = kv_pairs.begin();
         it != kv_pairs.end(); ++it) {
        VmodulePattern pattern(it->first);
        if (!base::StringToInt(it->second, &pattern.vlog_level)) {
            DLOG(WARNING) << "Parsed vlog level for \""
                          << it->first << "=" << it->second
                          << "\" as " << pattern.vlog_level;
        }
        vmodule_levels_.push_back(pattern);
    }
}

VlogInfo::~VlogInfo() { }

namespace {

    // Given a path, returns the basename with the extension chopped off
    // (and any -inl suffix).  We avoid using FilePath to minimize the
    // number of dependencies the logging system has.
    base::StringPiece GetModule(const base::StringPiece& file)
    {
        base::StringPiece module(file);
        base::StringPiece::size_type last_slash_pos = module.find_last_of("\\/");
        if (last_slash_pos != base::StringPiece::npos)
            module.remove_prefix(last_slash_pos + 1);
        base::StringPiece::size_type extension_start = module.rfind('.');
        module = module.substr(0, extension_start);
        static const char kInlSuffix[] = "-inl";
        static const int kInlSuffixLen = arraysize(kInlSuffix) - 1;
        if (module.ends_with(kInlSuffix))
            module.remove_suffix(kInlSuffixLen);
        return module;
    }

} // namespace

int VlogInfo::GetVlogLevel(const base::StringPiece& file) const
{
    if (!vmodule_levels_.empty()) {
        base::StringPiece module(GetModule(file));
        for (std::vector<VmodulePattern>::const_iterator it = vmodule_levels_.begin(); it != vmodule_levels_.end(); ++it) {
            base::StringPiece target(
                (it->match_target == VmodulePattern::MATCH_FILE) ? file : module);
            if (MatchVlogPattern(target, it->pattern))
                return it->vlog_level;
        }
    }
    return GetMaxVlogLevel();
}

void VlogInfo::SetMaxVlogLevel(int level)
{
    // Log severity is the negative verbosity.
    *min_log_level_ = -level;
}

int VlogInfo::GetMaxVlogLevel() const
{
    return -*min_log_level_;
}

bool MatchVlogPattern(const base::StringPiece& string,
    const base::StringPiece& vlog_pattern)
{
    base::StringPiece p(vlog_pattern);
    base::StringPiece s(string);
    // Consume characters until the next star.
    while (!p.empty() && !s.empty() && (p[0] != '*')) {
        switch (p[0]) {
        // A slash (forward or back) must match a slash (forward or back).
        case '/':
        case '\\':
            if ((s[0] != '/') && (s[0] != '\\'))
                return false;
            break;

        // A '?' matches anything.
        case '?':
            break;

        // Anything else must match literally.
        default:
            if (p[0] != s[0])
                return false;
            break;
        }
        p.remove_prefix(1), s.remove_prefix(1);
    }

    // An empty pattern here matches only an empty string.
    if (p.empty())
        return s.empty();

    // Coalesce runs of consecutive stars.  There should be at least
    // one.
    while (!p.empty() && (p[0] == '*'))
        p.remove_prefix(1);

    // Since we moved past the stars, an empty pattern here matches
    // anything.
    if (p.empty())
        return true;

    // Since we moved past the stars and p is non-empty, if some
    // non-empty substring of s matches p, then we ourselves match.
    while (!s.empty()) {
        if (MatchVlogPattern(s, p))
            return true;
        s.remove_prefix(1);
    }

    // Otherwise, we couldn't find a match.
    return false;
}

} // namespace logging
